Coarse Grid Design Methods and Structures

ABSTRACT

A layer of a mask material is deposited on a substrate. A beam of energy is scanned across the mask material in a rasterized linear pattern and in accordance with a scan pitch that is based on a pitch of conductive structure segments to be formed on the substrate. The beam of energy is defined to transform the mask material upon which the beam of energy is incident into a removable state. During scanning the beam of energy across the mask material, the beam of energy is turned on at locations where a conductive structure is to be formed on the substrate, and the beam of energy is turned off at locations where a conductive structure is not to be formed on the substrate.

CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application No. 61/487,247, filed May 17, 2011,entitled “Coarse Grid Design Methods and Structures,” the disclosure ofwhich is incorporated herein by reference in its entirety.

This application is also a continuation-in-part application under 35U.S.C. 120 of prior U.S. application Ser. No. 12/572,022, filed Oct. 1,2009, which is a continuation application under 35 U.S.C. 120 of priorU.S. application Ser. No. 12/212,562, filed Sep. 17, 2008, which is acontinuation application under 35 U.S.C. 120 of prior U.S. applicationSer. No. 11/683,402, filed Mar. 7, 2007, which claims priority under 35U.S.C. 119(e) to U.S. Provisional Patent Application No. 60/781,288,filed Mar. 9, 2006. Each of the above-identified applications isincorporated herein by reference in its entirety.

This application is also a continuation-in-part application under 35U.S.C. 120 of prior U.S. application Ser. No. 13/073,994, filed Mar. 28,2011, which is a continuation application under 35 U.S.C. 120 of priorU.S. application Ser. No. 12/013,342, filed Jan. 11, 2008, which claimspriority under 35 U.S.C. 119(e) to each of 1) U.S. Provisional PatentApplication No. 60/963,364, filed Aug. 2, 2007, and 2) U.S. ProvisionalPatent Application No. 60/972,394, filed Sep. 14, 2007. Each of theabove-identified applications is incorporated herein by reference in itsentirety.

This application is also a continuation-in-part application under 35U.S.C. 120 of prior U.S. application Ser. No. 12/753,795, filed Apr. 2,2010, which is a continuation application under 35 U.S.C. 120 of priorU.S. application Ser. No. 12/402,465, filed Mar. 11, 2009, which claimspriority under 35 U.S.C. 119(e) to each of 1) U.S. Provisional PatentApplication No. 61/036,460, filed Mar. 13, 2008, and 2) U.S. ProvisionalPatent Application No. 61/042,709, filed Apr. 4, 2008, and 3) U.S.Provisional Patent Application No. 61/045,953, filed Apr. 17, 2008, and4) U.S. Provisional Patent Application No. 61/050,136, filed May 2,2008. Each of the above-identified applications is incorporated hereinby reference in its entirety.

BACKGROUND

Until recently, integrated circuit (IC) scaling has been enabled to alarge extent by improvements in photolithography equipment resolutionand overlay. The resolution capability of the photolithography equipmentwas such that random logical functions could be drawn withtwo-dimensional (2D) bent shapes, with few restrictions on shapedimensions or relationships between shapes.

Traditional 2D designs have layout shape edges which can fall on a veryfine grid, such as on a 1 nm (nanometer) grid, by way of example. Adirect writing tool using a raster pattern needs to write along thefinest grid on each design/pattern layer of an integrated circuit device(sometimes called a mask layer) in order to correctly place all edges ofthe layout shapes. Also, 2D layout patterns need to be writtencompletely in two directions, resulting in a large amount of data foreach layer to be written. It is within this context that the presentinvention arises.

SUMMARY

In one embodiment, a method is disclosed for fabricating an integratedcircuit. The method includes depositing a layer of a mask material on asubstrate. The method also includes scanning a beam of energy across themask material in a rasterized linear pattern and in accordance with ascan pitch that is based on a pitch of conductive structure segments tobe formed on the substrate. The beam of energy is defined to transformthe mask material upon which the beam of energy is incident into aremovable state. During scanning the beam of energy across the maskmaterial, the beam of energy is turned on at locations where aconductive structure is to be formed on the substrate, and the beam ofenergy is turned off at locations where a conductive structure is not tobe formed on the substrate.

In one embodiment, a method is disclosed for fabricating an integratedcircuit. The method includes depositing a layer of a mask material on asubstrate. The method also includes scanning a beam of energy across themask material in a rasterized linear pattern and in accordance with ascan pitch that is equal to at least a width of the beam of energy asmeasured in a direction perpendicular to a scan direction of the beam ofenergy. The beam of energy is defined to transform the mask materialupon which the beam of energy is incident into a removable state. Duringscanning the beam of energy across the mask material, the beam of energyis turned on at locations where a conductive structure is to be formedon the substrate, and the beam of energy is turned off at locationswhere a conductive structure is not to be formed on the substrate.

Other aspects and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of a portion of a gate electrode layer of anexample logic circuit, in accordance with one embodiment of the presentinvention.

FIG. 2 shows a plan view of a possible scan pattern used to write “cuts”in the gate lines of the portion of the gate electrode layer of FIG. 1,in accordance with one embodiment of the present invention.

FIG. 3 shows a plan view of another possible scan pattern used to writethe cuts in the gate lines of the portion of the gate electrode layer ofFIG. 1, in accordance with one embodiment of the present invention.

FIG. 4 shows a plan view of a portion of a gate electrode layer of anexample logic circuit block including three rows of logic cells in acolumn, in accordance with one embodiment of the present invention.

FIG. 5 shows a plan view of a possible scan pattern used to write thecuts in the portion of the gate electrode layer of FIG. 4, in accordancewith one embodiment of the present invention.

FIG. 6 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a contact layer of an example logic circuit, inaccordance with one embodiment of the present invention.

FIG. 7 shows a plan view of a possible scan pattern used to write thediffusion and gate contacts in the example logic circuit of FIG. 6, inaccordance with one embodiment of the present invention.

FIG. 8 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a diffusion/active layer of an example circuit,in accordance with one embodiment of the present invention.

FIG. 9 shows a plan view of a possible scan pattern used to write thediffusion/active regions in the example circuit of FIG. 8, in accordancewith one embodiment of the present invention.

FIG. 10 shows a plan view of another possible scan pattern used to writethe diffusion/active regions in the example circuit of FIG. 8, inaccordance with one embodiment of the present invention.

FIG. 11 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a diffusion/active layer of an example circuit,in accordance with one embodiment of the present invention.

FIG. 12 shows a plan view of a possible scan pattern used to write thediffusion/active regions in the example circuit of FIG. 11, inaccordance with one embodiment of the present invention.

FIG. 13 shows a plan view of a portion of a gate electrode layer of anexample circuit that includes non-uniform gate line widths, inaccordance with one embodiment of the present invention.

FIG. 14 shows a plan view of a possible scan pattern used to write thegate lines in the example circuit of FIG. 13, in accordance with oneembodiment of the present invention.

FIG. 15 shows a plan view of a portion of a gate electrode layer of anexample circuit that includes non-uniform gate line widths and aconductive line segment oriented perpendicular to the gate lines, inaccordance with one embodiment of the present invention.

FIG. 16 shows a plan view of a possible scan pattern used to write thegate lines in the example circuit of FIG. 15, in accordance with oneembodiment of the present invention.

FIG. 17 shows a flowchart of a method of fabricating an integratedcircuit, in accordance with one embodiment of the present invention.

FIG. 18 shows a flowchart of a method of fabricating an integratedcircuit, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

As optical lithography has reached a cost-driven limit of the 193 nm ArFexcimer laser light source and a lens numerical aperture of 0.93 (or1.35 for water immersion systems), other approaches are required forfabrication of smaller IC feature sizes. One approach is spacer doublepatterning (SDP), in which the layout pattern is split into two parts,each of which can be processed with optical lithography equipment. Withspacer double/triple/quadruple/etc. patterning, pitch division canextend line patterns to smaller and smaller feature sizes until someother limit is reached. The SDP approach uses the following sequence toreduce the pattern pitch by a factor of two:

-   -   1. standard optical lithography to pattern a “core”    -   2. etch the core and remove the resist    -   3. deposit a different material which can be etched selectively        relative to the core    -   4. etch the deposited film, leaving sidewall material and the        core    -   5. etch the core, leaving only the sidewall material    -   6. cut the sidewall material to create separate parts    -   7. etch the underlying material using the sidewall material as        the mask    -   8. remove the sidewall material, leaving the underlying material        with the desired pattern.

A method of chip design and fabrication is described herein which uses acoarse grid layout. The coarse grid methods described herein may beimplemented with or without the multiple patterning approach discussedabove. In the coarse grid method, lines, cuts, and holes are positionedon the coarse grid. The coarse grid has a granularity set by therequirements of a particular IC layer. Structures to be fabricated on asemiconductor wafer are specified by lines, cuts, holes, or anycombination thereof, on a coarse grid. In one example embodiment, thelayout pattern of the structures to be fabricated can includeone-dimensional (1D) lines and cuts and holes, as needed. In anotherexample embodiment, the layout pattern of the structures to befabricated can include 1D line segments and holes, as needed. In anotherexample embodiment, the layout pattern of the structures to befabricated can be 1D and 2D coarse-grid line segments and holes, asneeded. The coarse grid applied to cuts and holes is also extendable.With electron beams, a feature size limit is on the order of less than10 nm.

FIG. 1 shows a plan view of a portion of a gate electrode layer of anexample logic circuit, in accordance with one embodiment of the presentinvention. The portion of the gate electrode layer includes gate lines101, 103, 105, 107, 109, 111, 113, 115. Each gate line 101, 103, 105,107, 109, 111, 113, 115 is defined to extend lengthwise in a firstdirection (Y direction). It should be understood that the gate linescorrespond to conductive structures formed within the portion of thegate electrode layer. The gate lines 101, 103, 105, 107, 109, 111, 113,115 in the example of FIG. 1 are shown to have uniform gate line-widthsW, as measured in a second direction (X direction) substantiallyperpendicular to the first direction (Y direction).

FIG. 2 shows a plan view of a possible scan pattern used to write “cuts”213, 215 in the gate lines of the portion of the gate electrode layer ofFIG. 1, in accordance with one embodiment of the present invention. Scanlines 201, 203, 205, 207, 209, 211 are centered and co-linear with agate line pattern corresponding to the gate lines 101, 103, 105, 107,109, 111, 113, 115. The scan pattern also includes retrace lines 202,204, 206, 208, 210. The beam is turned on at the cut 213, 215 locations.The shape of the cuts 213, 215 as shown in FIG. 2 is provided by way ofexample. In various embodiments, the shape of the cuts 213, 215 can berectangular or oval, among other shapes, as long as a size of the cut213, 215 as measured in a direction perpendicular to the scan lines,i.e., X direction in FIG. 2, is large enough to overlap the line to becut, even with worst-case layer-to-layer overlay misalignment. It shouldbe understood that the flexibility in the shape of the cuts 213, 215applies to other cuts discussed hereafter.

FIG. 3 shows a plan view of another possible scan pattern used to writethe cuts 213, 215 in the gate lines of the portion of the gate electrodelayer of FIG. 1, in accordance with one embodiment of the presentinvention. Scan lines 301, 303, 305, 307, 309, 311 are centered andco-linear with the gate line pattern corresponding to the gate lines101, 103, 105, 107, 109, 111, 113, 115. The scan pattern also includesretrace lines 302, 303, 306, 308, 310. The beam is turned on at the cut213, 215 locations.

FIG. 4 shows a plan view of a portion of a gate electrode layer of anexample logic circuit block including three rows of logic cells in acolumn, in accordance with one embodiment of the present invention. Afirst row 490 of logic cells includes gate lines 401, 402, 403, 404,405, 406. A second row 491 of logic cells includes gate lines 411, 412,413, 414, 415, 416, 417, 418. A third row 492 of logic cells includesgate lines 421, 422, 423, 424, 425, 426, 427, 428. Cuts 531A-536A,531B-536B, 531C-536C, 531D-536D, 532E-534E, 534F are formed in the gatelines on a common coarse grid in the X direction. In one embodiment,Metal-1 horizontal lines 451-481 corresponding to Metal-1 conductivestructures are shown by the dashed rectangles. In various embodiments,the cuts 531A-536A, 531B-536B, 531C-536C, 531D-536D, 532E-534E, 534F canbe positioned either on the Y grid formed by the Metal-1 horizontallines 451-481 or not, depending on the beam writer resolution along araster line.

FIG. 5 shows a plan view of a possible scan pattern used to write thecuts 531A-536A, 531B-536B, 531C-536C, 531D-536D, 532E-534E, 534F in theportion of the gate electrode layer of FIG. 4, in accordance with oneembodiment of the present invention. Scan lines 531, 532, 533, 534, 535,536 are centered and co-linear with the gate line pattern correspondingto the gate lines 401, 402, 403, 404, 405, 406, 411, 412, 413, 414, 415,416, 417, 418, 421, 422, 423, 424, 425, 426, 427, 428. The retrace linesare not shown in FIG. 5 to avoid cluttering the figure. However, itshould be understood that the retrace lines in the example of FIG. 5could be implemented as shown in the example embodiments of either FIG.2 or FIG. 3. Also, it should be understood that the beam scan lines 531,532, 533, 534, 535, 536 and initial lines of the gate electrodes mayextend above and below the top and bottom rows of cuts.

FIG. 6 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a contact layer of an example logic circuit, inaccordance with one embodiment of the present invention. The portion ofthe gate electrode layer includes gate lines 601, 602, 603, 604, 605,606, 607, 608 defined to extend lengthwise in a first direction Y. Inone embodiment, Metal-1 horizontal lines 651-661 corresponding toMetal-1 conductive structures are shown by the dashed rectangles. In oneembodiment, the Metal-1 horizontal lines 651-661 are centered on a fixedpitch (M1P) as measured in the Y direction. FIG. 6 also shows diffusioncontacts 711, 712, 713, 714, 715 corresponding to conductive structuresformed to physically contact a diffusion region, i.e., active region,underlying the portion of the gate electrode layer. For clarity, thediffusion/active regions are not shown in FIG. 6. FIG. 6 also shows gatecontacts 721, 722, 723, 724, 725 corresponding to conductive structuresformed to physically contact a conductive structure corresponding togate lines 603, 604, 607, 602, 608, respectively.

FIG. 7 shows a plan view of a possible scan pattern used to write thediffusion and gate contacts (711-715, 721-725) in the example logiccircuit of FIG. 6, in accordance with one embodiment of the presentinvention. The scan pattern includes scan lines 731-741. The retracelines are not show in FIG. 7 to avoid cluttering the figure. However, itshould be understood that the retrace lines in the example of FIG. 7could be implemented in a manner similar to that shown in the exampleembodiments of either FIG. 2 or FIG. 3. The scan lines 731-741 mayextend to the left and right of the logic cell or row of logic cellswithin which the example logic circuit resides. Also, it should beappreciated that the scan lines 731-741 are oriented in the horizontaldirection, i.e., X direction, to reduce the number of scan lines needed.

For example, since there are both diffusion and gate contacts (711-715,721-725) to be formed, the X pitch (CPX) of the contact scan is one-halfof the gate pitch (P) as shown in FIG. 6. Also, since the diffusion andgate contacts (711-715, 721-725) are to be placed along a metal line,the Y pitch (CPY) of the contact scan is substantially equal to theMetal-1 pitch (M1P) as shown in FIG. 6. In one embodiment, a width (W)of the gate lines 601-608 is about 22 nm (nanometers). In thisembodiment, the gate pitch (P) is about 90 nm, and the Metal-1 pitch(M1P) is about 70 nm. Because the Metal-1 pitch (M1P) of about 70 nm islarger than one-half of the gate pitch (P) (90 nm/2=45 nm), then a givenarea of the scan pattern can be covered with fewer scan lines using ascan pattern oriented in the horizontal direction (X direction), with aY pitch (CPY) of the contact scan that is substantially equal to theMetal-1 pitch (M1P). Although the horizontal scan shown in FIG. 7requires fewer scan lines, it should be understood that a vertical scandirection (Y direction) may be chosen if there are other constraintssuch as equipment hardware limitations.

FIG. 8 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a diffusion/active layer of an example circuit,in accordance with one embodiment of the present invention. The examplecircuit of FIG. 8 may be either a logic circuit or a memory circuit. Theportion of the gate electrode layer includes gate lines 801-808 definedto extend lengthwise in a first direction Y. The gate lines 801-808 arecentered on a gate pitch (P) as measured in the X direction. In oneembodiment, Metal-1 horizontal lines 851-859 corresponding to Metal-1conductive structures are shown by the dashed rectangles. In oneembodiment, the Metal-1 horizontal lines 851-859 are centered on a fixedpitch (M1P) as measured in the Y direction.

FIG. 8 also shows diffusion/active regions 821 and 823. As shown in FIG.8, the diffusion/active regions can be divided into strips which eachhave a width as measured in the Y direction that is a fraction of theMetal-1pitch (M1P). For example, in some embodiments, the strips intowhich the diffusion/active regions 821, 823 are divided have a width asmeasured in the Y direction that is either one-fourth (¼) or one-eighth(⅛) of the Metal-1 pitch (M1P). In the example of FIG. 8, the centers ofthe diffusion/active regions 821, 823 are vertically aligned, such thata single line extending in the Y direction passes through the centers ofthe diffusion/active regions 821, 823. However, it should be understoodthat in other embodiments the diffusion/active regions 821, 823 may notbe vertically aligned.

FIG. 9 shows a plan view of a possible scan pattern used to write thediffusion/active regions 821, 823 in the example circuit of FIG. 8, inaccordance with one embodiment of the present invention. The scanpattern includes scan lines 901-934. The retrace lines are not show inFIG. 9 to avoid cluttering the figure. However, it should be understoodthat the retrace lines in the example of FIG. 9 could be implemented ina manner similar to that shown in the example embodiments of either FIG.2 or FIG. 3. The scan lines 901-934 are oriented in the horizontaldirection (X direction) and may extend to the left and/or right of thelogic/memory cell or row of logic/memory cells in which the examplecircuit is formed. In this example embodiment, the scan direction isperpendicular to a length direction of the gate lines 801-808. Theexample scan pattern shown in FIG. 9 has a scan pitch (DSP) as measuredin the Y direction that is one-fourth (¼) of the Metal-1 pitch (M1P) asmeasured in the Y direction. A scan beam cross-section 940 size asmeasured in the Y direction is equal to a width of a scan line plus somesmall extension (e.g., 1 nm to 5 nm, by way of example) to account foroverlay as the beam is scanned side-to-side.

As shown in FIG. 9, scan lines 908-913 and 922-927 require switching ofthe beam (“on” for negative photoresist, “off” for positive photoresist)to produce strips of the diffusion/active regions 823 and 821,respectively. Also, scan lines 901-907, 914-921, 928-934 do not requireswitching of the beam. It should be appreciated that the scan pitch(DSP), i.e., raster size, of one-fourth of the Metal-1 pitch (M1P) isstill relatively coarse as compared to a 1 nm or finer scan pitch thatis required to draw/form conventional diffusion/active regions.

FIG. 10 shows a plan view of another possible scan pattern used to writethe diffusion/active regions 821, 823 in the example circuit of FIG. 8,in accordance with one embodiment of the present invention. The scanpattern includes scan lines 1001-1008. The scan lines 1001-1008 areoriented in the vertical direction (Y direction) and may extend aboveand/or below the logic/memory cell or row of logic/memory cells in whichthe example circuit is formed. In this example embodiment, the scandirection is parallel to a length direction of the gate lines 801-808.The retrace lines are not shown in FIG. 10 to avoid cluttering thefigure. However, it should be understood that the retrace lines in theexample of FIG. 10 could be implemented in a manner similar to thatshown in the example embodiments of either FIG. 2 or FIG. 3.

The example scan pattern shown in FIG. 10 has a scan pitch (DSP1) asmeasured in the X direction that is substantially equal to a pitch (P)of the gate lines 801-808 as measured in the X direction as shown inFIG. 8. In one embodiment, a scan beam cross-section 1011 size asmeasured in the X direction is substantially equal to the pitch (P) ofthe gate lines 801-808 plus some small extension (e.g., 1 nm to 5 nm, byway of example) to account for overlay as the beam is scanned verticallyin the Y direction.

As shown in FIG. 10, scan lines 1002-1007 require switching of the beam(”on” for negative photoresist, “off” for positive photoresist) toproduce strips of the diffusion/active regions 821 and 823. Also, scanlines 1001 and 1008 do not require switching of the beam. It should beappreciated that the scan pitch (DSP1), i.e., raster size, which issubstantially equal to the gate pitch (P) is very coarse as compared toa 1 nm or finer scan pitch that is required to draw/form conventionaldiffusion/active regions. It should also be appreciated that forvertical scanning in the Y direction (parallel to the length directionof the gate lines 801-808), the diffusion/active region 821, 823 edgeplacement depends on the timing accuracy of the beam switching (i.e.,beam turning on or off depending on the type of photoresist used) and isnot necessarily tied to a fraction of the Metal-1 pitch, such asdiscussed above with regard to the example scan pattern of FIG. 9.

FIG. 11 shows a plan view of a portion of a gate electrode layer and acorresponding portion of a diffusion/active layer of an example circuit,in accordance with one embodiment of the present invention. The examplecircuit of FIG. 11 may be either a logic circuit or a memory circuit.The portion of the gate electrode layer includes gate lines 1101-1108defined to extend lengthwise in a first direction (Y direction). Thegate lines 1101-1108 are centered on a gate pitch (P) as measured in theX direction. In one embodiment, Metal-1 horizontal lines 1151-1159corresponding to Metal-1 conductive structures are shown by the dashedrectangles. In one embodiment, the Metal-1 horizontal lines 1151-1159are centered on a fixed pitch (M1P) as measured in the Y direction.

FIG. 11 also shows diffusion/active regions 1121, 1123, 1125, 1127. Inthe example of FIG. 11, the centers of the diffusion/active regions 1125and 1127 are vertically aligned and the centers of diffusion/activeregions 1121 and 1123 are vertically aligned, such that a single lineextending in the Y direction passes through the centers of thediffusion/active regions 1125 and 1127, and such that another singleline extending in the Y direction passes through the centers of thediffusion/active regions 1121 and 1123. However, it should be understoodthat in other embodiments the diffusion/active regions 1125 and 1127and/or 1121 and 1123 may not be vertically aligned so long as theirrespective vertical edges are positioned according to a coarse grid ofthe scan pattern.

For horizontal scanning in the X direction (perpendicular to the gatelines 1101-1108), the diffusion/active regions 1121, 1123, 1125, 1127can be divided into strips which each have a width as measured in the Ydirection that is a fraction of the Metal-1pitch (M1P). For example, insome embodiments, the strips into which the diffusion/active regions1121, 1123, 1125, 1127 are divided have a width as measured in the Ydirection that is either one-fourth (¼) or one-eighth (⅛) of the Metal-1pitch (M1P). For vertical scanning in the Y direction (parallel to thegate lines 1101-1108) the horizontal edge placement of thediffusion/active regions 1121, 1123, 1125, 1127 depends on the timingaccuracy of the beam switching (i.e., beam turning on or off dependingon the type of photoresist used) and is not necessarily tied to afraction of the Metal-1 pitch, such as discussed above with regard tothe example scan pattern of FIG. 9.

FIG. 12 shows a plan view of a possible scan pattern used to write thediffusion/active regions 1121, 1123, 1125, 1127 in the example circuitof FIG. 11, in accordance with one embodiment of the present invention.The scan pattern includes scan lines 1201-1214. The scan lines 1201-1214are oriented in the vertical direction (Y direction) and may extendabove and/or below the logic/memory cell or row of logic/memory cells inwhich the example circuit is formed. In this example embodiment, thescan direction is parallel to a length direction of the gate lines1101-1108. The retrace lines are not shown in FIG. 12 to avoidcluttering the figure. However, it should be understood that the retracelines in the example of FIG. 12 could be implemented in a manner similarto that shown in the example embodiments of either FIG. 2 or FIG. 3.

The example scan pattern shown in FIG. 12 has a scan pitch (DSP2) asmeasured in the X direction that is substantially equal to one-half (½)of the gate pitch (P) of the gate lines 1101-1108 as measured in the Xdirection as shown in FIG. 11. Therefore, each of the scan lines1201-1214 is substantially aligned with either a lengthwise centerlineof one of the gate lines 1101-1108, or one of the midpoint locationsbetween the lengthwise centerlines of a neighboring pair of the gatelines 1101-1108.

In one embodiment, a scan beam cross-section 1231 size as measured inthe X direction is substantially equal to one-half (1/2) of the gatepitch (P) of the gate lines 801-808 plus some small extension (e.g., 1nm to 5 nm, by way of example) to account for overlay as the beam isscanned vertically in the Y direction. As shown in FIG. 12, scan lines1202-1210 and 1212 require switching of the beam (”on” for negativephotoresist, “off” for positive photoresist) to produce strips of thediffusion/active regions 1121, 1123, 1125, 1127. Also, scan lines 1201,1211, 1214 do not require switching of the beam.

It should be appreciated that the scan pitch (DSP2), i.e., raster size,which is substantially equal to one-half (½) of the gate pitch (P) isvery coarse as compared to a 1 nm or finer scan pitch that is requiredto draw/form conventional diffusion/active regions. It should also beappreciated that for vertical scanning in the Y direction (parallel tothe length direction of the gate lines 1101-1108), the edge placement ofthe diffusion/active regions 1121, 1123, 1125, 1127 depends on thetiming accuracy of the beam switching (i.e., beam turning on or offdepending on the type of photoresist used) and is not necessarily tiedto a fraction of the Metal-1 pitch, such as discussed above with regardto the example scan pattern of FIG. 9. Therefore, the final verticalsizes of the diffusion/active regions 1121, 1123, 1125, 1127 aredetermined by the accuracy of the beam switching.

FIG. 13 shows a plan view of a portion of a gate electrode layer of anexample circuit that includes non-uniform gate line widths, inaccordance with one embodiment of the present invention. The examplecircuit of FIG. 13 may be either a logic circuit or a memory circuit.The portion of the gate electrode layer includes gate lines 1301-1308.It should be understood that the gate lines 1301-1308 correspond toconductive structures formed within the portion of the gate electrodelayer. Each gate line 1301-1308 is defined to extend lengthwise in afirst direction Y. Gate lines 1301, 1302, 1304, 1306, 1308 have a firstwidth (W1) as measured in the X direction. Gate lines 1303, 1305, 1307have a second width (W2) as measured in the X direction. The secondwidth (W2) is different than the first width (W1). In one embodiment,Metal-1 horizontal lines 1351-1361 corresponding to Metal-1 conductivestructures are shown by the dashed rectangles. In one embodiment, theMetal-1 horizontal lines 1351-1361 are centered on a fixed pitch (M1P)as measured in the Y direction.

FIG. 14 shows a plan view of a possible scan pattern used to write thegate lines 1301-1308 in the example circuit of FIG. 13, in accordancewith one embodiment of the present invention. The scan pattern includesscan lines 1401-1421. The retrace lines are not shown in FIG. 14 toavoid cluttering the figure. However, it should be understood that theretrace lines in the example of FIG. 14 could be implemented in a mannersimilar to that shown in the example embodiments of either FIG. 2 orFIG. 3. The scan lines 1401-1421 are oriented in the horizontaldirection (X direction) and may extend to the left and/or right of thelogic/memory cell or row of logic/memory cells in which the examplecircuit is formed. In this example embodiment, the scan direction isperpendicular to a length direction of the gate lines 1301-1308.

The example scan pattern shown in FIG. 14 has a scan pitch (SP2) asmeasured in the Y direction that is one-half (½) of the Metal-1 pitch(M1P) as measured in the Y direction. A scan beam cross-section 1441size as measured in the Y direction is equal to a width of a scan line(about one-half (½) of the Metal-1 pitch (M1P)) plus some smallextension (e.g., 1 nm to 5 nm, by way of example) to account for overlayas the beam is scanned side-to-side.

As shown in FIG. 14, scan lines 1402-1419 require switching of the beam(”on” for negative photoresist, “off” for positive photoresist) toproduce portions of the gate lines 1301-1308. Also, scan lines 1401 and1421 do not require switching of the beam. Each of scan lines 1402-1420is switched to create portions of the gate lines 1301-1308 of thedifferent widths W1, W2. Also, each of scan lines 1411 and 1415 isswitched to create end gaps 1451 and 1452, respectively. In thisembodiment, the beam switching has a sufficient temporal resolution toallow for writing/creating the portions of the gate lines 1301-1308 ofdifferent widths W1, W2.

It should be appreciated that the scan pitch (SP2), i.e., raster size,of one-half (½) of the Metal-1 pitch (M1P) (e.g., SP2=35 nm for 22 nmCMOS node) is still relatively coarse as compared to a 1 nm or finerscan pitch that is required to draw/form conventional gate lines. Itshould also be appreciated that while the scan pitch (SP2) is not aslarge, i.e., coarse, as the scan pitch shown in the examples of FIG. 2or 3, the scan pitch (SP2) and corresponding scan pattern of FIG. 14allow for writing/creating lines of different widths, as measured in thescan direction, which can be important in forming gate lines and/ordiffusion/active regions. In one embodiment, in order to control thebeam switching precisely enough to provide sufficient critical dimension(CD) control as required for gate electrode formation, the beam scanningmay be performed in a uni-directional manner, as opposed to thebi-directional manner shown in FIG. 14.

FIG. 15 shows a plan view of a portion of a gate electrode layer of anexample circuit that includes non-uniform gate line widths and aconductive line segment oriented perpendicular to the gate lines, inaccordance with one embodiment of the present invention. The portion ofthe gate electrode layer includes gate lines 1501-1508. It should beunderstood that the gate lines 1501-1508 correspond to conductivestructures formed within the portion of the gate electrode layer. Eachgate line 1501-1508 is defined to extend lengthwise in a first directionY. Gate lines 1501, 1502, 1504, 1506, 1508 have a first width (W1) asmeasured in the X direction. Gate lines 1503, 1505, 1507 have a secondwidth (W2) as measured in the X direction. The second width (W2) isdifferent than the first width (W1). The portion of the gate electrodelayer also includes the conductive line segment 1511 oriented in the Xdirection perpendicular to the gate lines 1501-1508, so as to extendbetween and contact gate lines 1504 and 1507. It should be understoodthat the conductive line segment 1511 corresponds to a conductivestructure formed within the portion of the gate electrode layer. In oneembodiment, Metal-1 horizontal lines 1551-1561 corresponding to Metal-1conductive structures are shown by the dashed rectangles. In oneembodiment, the Metal-1 horizontal lines 1551-1561 are centered on afixed pitch (M1P) as measured in the Y direction.

FIG. 16 shows a plan view of a possible scan pattern used to write thegate lines 1301-1308 in the example circuit of FIG. 15, in accordancewith one embodiment of the present invention. The scan pattern includesscan lines 1601-1621. The retrace lines are not shown in FIG. 16 toavoid cluttering the figure. However, it should be understood that theretrace lines in the example of FIG. 16 could be implemented in a mannersimilar to that shown in the example embodiments of either FIG. 2 orFIG. 3. The scan lines 1601-1621 are oriented in the horizontaldirection (X direction) and may extend to the left and/or right of thelogic/memory cell or row of logic/memory cells in which the examplecircuit is formed. In this example embodiment, the scan direction isperpendicular to a length direction of the gate lines 1501-1508.

The example scan pattern shown in FIG. 16 has a scan pitch (SP2) asmeasured in the Y direction that is one-half (½) of the Metal-1 pitch(M1P) as measured in the Y direction. In one embodiment, a scan beamcross-section 1641 size as measured in the Y direction is equal to awidth of a scan line (about one-half (½) of the Metal-1 pitch (M1P))plus some small extension (e.g., 1 nm to 5 nm, by way of example) toaccount for overlay as the beam is scanned side-to-side.

As shown in FIG. 16, scan lines 1602-1619 require switching of the beam(”on” for negative photoresist, “off” for positive photoresist) toproduce portions of the gate lines 1501-1508 and the conductive linesegment 1511. Also, scan lines 1601 and 1621 do not require switching ofthe beam. Each of scan lines 1602-1620 is switched to create portions ofthe gate lines 1501-1508 of the different widths W1, W2. Also, each ofscan lines 1611 and 1613 is switched to create end gaps 1651 and 1652,respectively. Also, scan line 1612 is switched to create the conductiveline segment 1511. It should be appreciated that in this manner the beamcan be switched to create line segments that extend in a lengthwisedirection perpendicular to the gate lines 1501-1508.

In one embodiment, the line-width of the conductive line segment 1511 asmeasured in the Y direction is determined by the beam cross-section sizeas measured in the Y direction. In this embodiment, the line-width ofthe conductive line segment 1511 as measured in the Y direction issubstantially equal to one-half (½) of the Metal-1 pitch (M1P), sincethe line-width of the conductive line segment 1511 is defined by thewidth of the beam as measured in the Y direction, as opposed to thetemporal accuracy of the beam switching. However, in this embodiment, itshould be understood that the beam switching has a sufficient temporalresolution to allow for writing/creating the portions of the gate lines1501-1508 of different widths W1, W2, the end gaps 1651, 1652, and theperpendicularly oriented (in the X direction) conductive line segment1511.

It should be appreciated that the scan pitch (SP2), i.e., raster size,of one-half (½) of the Metal-1 pitch (M1P) (e.g., SP2=35 nm for 22 nmCMOS node) is still relatively coarse as compared to a 1 nm or finerscan pitch that is required to draw/form conventional gate lines. Itshould also be appreciated that while the scan pitch (SP2) is not aslarge, i.e., coarse, as the scan pitch shown in the examples of FIG. 2or 3, the scan pitch (SP2) and corresponding scan pattern of FIG. 16allows for writing/creating lines of different widths, as measured inthe scan direction, which can be important in forming gate lines and/ordiffusion/active regions. Also, the scan pitch (SP2) allows forwriting/creating line segments that are oriented perpendicular to thegate lines 1501-1508, i.e., that are oriented parallel to the scandirection. Additionally, the scan pitch (SP2) allows for cutting of gatelines to form eng gaps, such as end gaps 1651 and 1652. In oneembodiment, in order to control the beam switching precisely enough toprovide sufficient critical dimension (CD) control as required for gateelectrode formation, the beam scanning may be performed in auni-directional manner, as opposed to the bi-directional manner shown inFIG. 16.

The Dynamic Array Architecture developed by Tela Innovations, Inc., isdescribed in part in U.S. Pat. No. 7,446,352, entitled “Dynamic ArrayArchitecture,” and in part in U.S. Pat. No. 7,917,879, entitled“Semiconductor Device with Dynamic Array Section,” each of which isincorporated herein by reference in its entirety. Use of the DynamicArray Architecture implemented with “lines” and “cuts,” as discussedherein, can force all features onto a “coarse grid.” For example, allgate electrode cuts can be on a gate pitch, so a beam writer (laser orelectron) would only need to make one pass along the direction of a gateline to write the cuts. Since the gate pitch is about 80 nm for the 22nm CMOS node, an improvement in write time by a factor of 80 or more canbe realized as compared to a 1 nm grid. Further improvements in writetime can be achieved with parallel or multiple beams. Also, worse-caselayers like the diffusion/active layer could be designed with granularwidths and locations such that it could be written with a relativelycoarse grid. For example, using a grid of one-eighth (⅛) of the Metal-1pitch would allow writing the pattern about 10 times faster than with a1 nm fine grid. Also, “hole” patterns such as contact and via-N can beplaced on a coarse grid layout within the Dynamic Array Architecture.

It should be further appreciated that the coarse grid methods describedherein are scalable through use of multiple patterning. For example,lines can be created using “Spacer Double Patterning” once or multipletimes to achieve pitch division by 2 (PD2), 4 (PD4), 8 (PD8), etc., andachieve line pitches of 30 nm and below. In one example, at the 22 nmCMOS technology node, the Metal-1 pitch is about 70 nm, with a Metal-1width of about 36 nm and a Metal-1-to-Metal-1 spacing of about 34 nm.This Metal-1 pitch and sizing cannot be directly patterned with 193immersion lithography, but can be patterned using PD2 spacer doublepatterning.

In one embodiment, a relaxed version the Dynamic Array Architecture canbe implemented in which all lines and holes are written with a coarsebeam which makes two passes per pitch. This will allow the beam to writelines or cuts in either the normal line channel or the normal spacechannel. This embodiment may cause a reduction in throughput, but may beuseful for special layout cases.

As mentioned above, the invention described herein can use the TelaInnovations, Inc., Dynamic Array Architecture (i.e., gridded designstyle). However, it should be understood that the invention is notlimited to the Dynamic Array Architecture design style. Also, while CMOStransistors may be formed in accordance with the examples describedherein, it should be understood that other components can be formed inan analogous fashion. It should also be noted that the Dynamic ArrayArchitecture can be implemented with a coarse grid in the X and Ydirections to facilitate identification of the locations of objects liketransistors, contacts, and gaps in lines, i.e., linear conductivestructures. The linear conductive structures can be positioned on and/oraccording to the grids.

FIG. 17 shows a flowchart of a method of fabricating an integratedcircuit, in accordance with one embodiment of the present invention. Themethod includes an operation 1701 for depositing a layer of a maskmaterial on a substrate. In one embodiment, the mask material is aphotoresist material. The method also includes an operation 1703 forscanning a beam of energy across the mask material in a rasterizedlinear pattern and in accordance with a scan pitch that is based on apitch of conductive structure segments to be formed on the substrate. Inone embodiment, the beam of energy is defined to transform the maskmaterial upon which the beam of energy is incident into a removablestate. In various embodiments, the beam of energy is either an electronbeam or a laser beam. The method further includes an operation 1705 forturning the beam of energy on at locations where a conductive structureis to be formed on the substrate during scanning the beam of energyacross the mask material. Also, in operation 1705, the beam of energy isturned off at locations where a conductive structure is not to be formedon the substrate.

In one embodiment, the scan pitch is equal to and aligned with the pitchof conductive structure segments to be formed on the substrate. In oneinstance of this embodiment, the conductive structure segments to beformed on the substrate are gate level conductive structure segments.Also, some of the gate level conductive structure segments form one ormore transistor gate electrodes.

In one embodiment, the scan pitch is one-half of a gate electrode pitch,and the scan pitch is aligned with the gate electrode pitch. In oneinstance of this embodiment, the conductive structure segments to beformed on the substrate are contact structures. The contact structurescan include at least one gate contact and at least one diffusioncontact.

In one embodiment, the scan pitch is equal to and aligned with aninterconnect level conductive structure pitch. In one instance of thisembodiment, the conductive structure segments to be formed on thesubstrate are interconnect level conductive structures. In anotherinstance of this embodiment, the conductive structure segments to beformed on the substrate are via structures.

FIG. 18 shows a flowchart of a method of fabricating an integratedcircuit, in accordance with one embodiment of the present invention. Themethod includes an operation 1801 for depositing a layer of a maskmaterial on a substrate. In one embodiment, the mask material is aphotoresist material. The method also includes an operation 1803 forscanning a beam of energy across the mask material in a rasterizedlinear pattern and in accordance with a scan pitch that is equal to atleast a width of the beam of energy as measured in a directionperpendicular to a scan direction of the beam of energy. In variousembodiments, the beam of energy is either an electron beam or a laserbeam. In one embodiment, the scan pitch is substantially equal to thewidth of the beam of energy. In one embodiment, the beam of energy isdefined to transform the mask material upon which the beam of energy isincident into a removable state. The method further includes anoperation 1805 for turning the beam of energy on at locations where aconductive structure is to be formed on the substrate during scanningthe beam of energy across the mask material. The operation 1805 alsoincludes turning the beam of energy off at locations where a conductivestructure is not to be formed on the substrate.

In one embodiment, the beam of energy is turned on as the beam of energyis scanned perpendicularly across locations corresponding to a pitch ofconductive structure segments to be formed on the substrate. The methodcan also include an operation for controlling a time period during whichthe beam of energy is turned on at each location corresponding to thepitch of conductive structure segments to be formed on the substrate, soas to control a width of the conductive structure segments to be formedon the substrate. Also, the method can include an operation for turningthe beam of energy on between one or more locations corresponding to thepitch of conductive structure segments to be formed on the substrate, soas to transform the mask material between the one or more locations toprovide for formation of a conductive structure that extends between theone or more locations.

It should be understood that in one embodiment the invention describedherein can be embodied as computer readable code on a computer readablemedium. For example, the computer readable code can include computerexecutable program instructions for operating the energy beam scanner.The computer readable medium mentioned herein is any data storage devicethat can store data which can thereafter be read by a computer system.Examples of the computer readable medium include hard drives, networkattached storage (NAS), read-only memory, random-access memory, CD-ROMs,CD-Rs, CD-RWs, magnetic tapes, and other optical and non-optical datastorage devices. The computer readable medium can also be distributedover a network of coupled computer systems so that the computer readablecode is stored and executed in a distributed fashion.

Any of the operations described herein that form part of the inventionare useful machine operations. The invention also relates to a device oran apparatus for performing these operations. The apparatus may bespecially constructed for the required purpose, such as a specialpurpose computer. When defined as a special purpose computer, thecomputer can also perform other processing, program execution orroutines that are not part of the special purpose, while still beingcapable of operating for the special purpose. Alternatively, theoperations may be processed by a general purpose computer selectivelyactivated or configured by one or more computer programs stored in thecomputer memory, cache, or obtained over a network. When data isobtained over a network the data maybe processed by other computers onthe network, e.g., a cloud of computing resources.

The embodiments of the present invention can also be defined as amachine that transforms data from one state to another state. The datamay represent an article, that can be represented as an electronicsignal and electronically manipulate data. The transformed data can, insome cases, be visually depicted on a display, representing the physicalobject that results from the transformation of data. The transformeddata can be saved to storage generally, or in particular formats thatenable the construction or depiction of a physical and tangible object.In some embodiments, the manipulation can be performed by a processor.In such an example, the processor thus transforms the data from onething to another. Still further, the methods can be processed by one ormore machines or processors that can be connected over a network. Eachmachine can transform data from one state or thing to another, and canalso process data, save data to storage, transmit data over a network,display the result, or communicate the result to another machine.

It should be further understood that the methods disclosed herein can beused to manufacture part of a semiconductor device or chip. In thefabrication of semiconductor devices such as integrated circuits, memorycells, and the like, a series of manufacturing operations are performedto define features on a semiconductor wafer, i.e., substrate. The waferincludes integrated circuit devices in the form of multi-levelstructures defined on a silicon substrate. At a substrate level,transistor devices with diffusion regions are formed. In subsequentlevels, interconnect metallization lines are patterned and electricallyconnected to the transistor devices to define a desired integratedcircuit device. Also, patterned conductive layers are insulated fromother conductive layers by dielectric materials.

While this invention has been described in terms of several embodiments,it will be appreciated that those skilled in the art upon reading thepreceding specifications and studying the drawings will realize variousalterations, additions, permutations and equivalents thereof. Therefore,it is intended that the present invention includes all such alterations,additions, permutations, and equivalents as fall within the true spiritand scope of the invention.

What is claimed is:
 1. A method of fabricating an integrated circuit,comprising: depositing a layer of a mask material on a substrate;scanning a beam of energy across the mask material in a rasterizedlinear pattern and in accordance with a scan pitch that is based on apitch of conductive structure segments to be formed on the substrate,wherein the beam of energy is defined to transform the mask materialupon which the beam of energy is incident into a removable state; andduring scanning the beam of energy across the mask material, turning thebeam of energy on at locations where a conductive structure is to beformed on the substrate, and turning the beam of energy off at locationswhere a conductive structure is not to be formed on the substrate. 2.The method of claim 1, wherein the scan pitch is equal to and alignedwith the pitch of conductive structure segments to be formed on thesubstrate.
 3. The method of claim 2, wherein the conductive structuresegments to be formed on the substrate are gate level conductivestructure segments.
 4. The method of claim 3, wherein some of the gatelevel conductive structure segments form one or more transistor gateelectrodes.
 5. The method of claim 1, wherein the scan pitch is one-halfof a gate electrode pitch, and wherein the scan pitch is aligned withthe gate electrode pitch.
 6. The method of claim 5, wherein theconductive structure segments to be formed on the substrate are contactstructures.
 7. The method of claim 6, wherein the contact structuresinclude at least one gate contact and at least one diffusion contact. 8.The method of claim 1, wherein the scan pitch is equal to and alignedwith an interconnect level conductive structure pitch.
 9. The method ofclaim 8, wherein the conductive structure segments to be formed on thesubstrate are interconnect level conductive structures.
 10. The methodof claim 8, wherein the conductive structure segments to be formed onthe substrate are via structures.
 11. The method of claim 1, wherein thebeam of energy is an electron beam.
 12. The method of claim 1, whereinthe beam of energy is a laser beam.
 13. The method of claim 1, whereinthe mask material is a photoresist material.
 14. A method of fabricatingan integrated circuit, comprising: depositing a layer of a mask materialon a substrate; scanning a beam of energy across the mask material in arasterized linear pattern and in accordance with a scan pitch that isequal to at least a width of the beam of energy as measured in adirection perpendicular to a scan direction of the beam of energy,wherein the beam of energy is defined to transform the mask materialupon which the beam of energy is incident into a removable state; andduring scanning the beam of energy across the mask material, turning thebeam of energy on at locations where a conductive structure is to beformed on the substrate, and turning the beam of energy off at locationswhere a conductive structure is not to be formed on the substrate. 15.The method of claim 14, wherein the scan pitch is substantially equal tothe width of the beam of energy.
 16. The method of claim 14, wherein thebeam of energy is turned on as the beam of energy is scannedperpendicularly across locations corresponding to a pitch of conductivestructure segments to be formed on the substrate.
 17. The method ofclaim 16, further comprising: controlling a time period during which thebeam of energy is turned on at each location corresponding to the pitchof conductive structure segments to be formed on the substrate so as tocontrol a width of the conductive structure segments to be formed on thesubstrate.
 18. The method of claim 17, further comprising: turning thebeam of energy on between one or more locations corresponding to thepitch of conductive structure segments to be formed on the substrate soas to transform the mask material between the one or more locations toprovide for formation of a conductive structure that extends between theone or more locations.
 19. The method of claim 14, wherein the beam ofenergy is either an electron beam or a laser beam.
 20. The method ofclaim 14, wherein the mask material is a photoresist material.